Add .env.example with default port configuration

.env.example

@@ -1,19 +1,20 @@
-# MySQL (docker-compose 内部默认值，wizard 配置优先)
+# HarborForge Environment Variables
+# Copy to .env and customize as needed
+
+# Port configurations (defaults shown)
+WIZARD_PORT=8080
+MYSQL_PORT=3306
+BACKEND_PORT=8000
+FRONTEND_PORT=3000
+
+# Database (optional overrides)
 MYSQL_ROOT_PASSWORD=harborforge_root
 MYSQL_DATABASE=harborforge
 MYSQL_USER=harborforge
 MYSQL_PASSWORD=harborforge_pass
-MYSQL_PORT=3306
 
-# Backend
+# Security
 SECRET_KEY=change_me_in_production
+
+# Logging
 LOG_LEVEL=INFO
-BACKEND_PORT=8000
-
-# AbstractWizard (localhost only)
-WIZARD_PORT=18080
-
-# Frontend
-FRONTEND_PORT=3000
-VITE_API_BASE=/api
-VITE_WIZARD_PORT=18080